Conventional paint rollers are composed of two parts: a wire roller that freely spins on an axle as the roller move across a surface, and a roller cover, a fabric-covered cylinder which slips onto the wire roller. The wire roller has a handle for the user to grasp. When attached to the wire roller, the roller cover is made to absorb paint from a reservoir, such as a paint pan. This absorbed paint is then applied to a surface by a rolling action. Currently, applicators of liquid surface coating materials such as paints use a fabric covered roller to rapidly apply these coatings to surfaces. While these rollers work well on flat surfaces, they cannot be used to apply surface coatings into deep corners where two or more surfaces meet. These deep corners occur, for example, in a room where two walls meet, or where a ceiling and one or more walls come together. To overcome this limitation of conventional rollers or covers, corners had been coated using a brush or paint pad, which is a slow and tedious process. In painting a room with conventional rollers, painting of corners with a brush or painting pad is the limiting factor in the expeditious completion of the job.
As painting technology advanced, a number of corner-painting devices have been patented. These corner-painting rollers are of two basic types:                1. rollers which have the paint fabric solidly attached to the roller; and        2. rollers wherein the paint fabric is not solidly attached to the roller.        
For corner-painting rollers which have the fabric solidly attached to the roller body, the roller is assembled with nuts and bolts. This assembly requires the use of wrenches, which are not always readily available during a coating operation, and which occasionally fail to work properly. The nuts and bolts of these rollers protrude from the device and will be covered with coating material during use of the roller. This results in a difficult and messy disassembly of these rollers, with fouling of hands and wrenches with the coating material. The protruding nuts and bolts of some of these corner-painting rollers can dig into the surface being coated, gouging the surface and marring the finish.
In the case of corner-painting rollers where the fabric is not firmly or permanently attached to the roller cover, the fabric fits over the body of the roller cover like a stocking, with no nuts and bolts required for assembly. The roller-cover fabric is slipped over the roller cover body which is attached to the axle of a roller. This assembly is a two-step process. Since the fabric of this roller cover is not permanently attached to the roller cover body mechanically or with adhesive, it is not anchored in place. When this roller is in use, the fabric may be warped, with a possible complete detachment of the fabric from the cover body. This inevitably leads to marring of the wall finish, messy cleanups, and optionally messy and time consuming reattachments of the paint fabric to the roller cover body. These problems are exacerbated when the roller is used quickly.
Accessories for loading rollers with paint or other coating materials must be efficient in filling rollers with coating materials. For adequately loading a roller with paint or other coating material, the device must provide the painter adequate space in the reservoir for manipulating the roller. This space requirement is, of course, somewhat dependent on the size of the roller, and is used to coat the roller evenly and to drop off excess paint into the paint reservoir.
Adequately sized painting accessories cannot fit into a paint can unless the roller is too small to be useful, because there would not be sufficient room to properly load the roller with paint.